IN  PDEVICE_OBJECT DeviceObject,
  IN  ULONG SectorSize,
  IN  ULONG PartitionNumber,
  IN  ULONG PartitionType

Routine Description:

    This routine is invoked when a disk device driver is asked to set the
    partition type in a partition table entry via an I/O control code.  This
    control code is generally issued by the format utility just after it
    has formatted the partition.  The format utility performs the I/O control
    function on the partition and the driver passes the address of the base
    physical device object and the number of the partition associated with
    the device object that the format utility has open.  If this routine
    returns success, then the disk driver should updates its notion of the
    partition type for this partition in its device extension.


    DeviceObject - Pointer to the base physical device object for the device
        on which the partition type is to be set.

    SectorSize - Supplies the size of a sector on the disk in bytes.

    PartitionNumber - Specifies the partition number on the device whose
        partition type is to be changed.

    PartitionType - Specifies the new type for the partition.

Return Value:

    The function value is the final status of the operation.


    This routine is synchronous.  Therefore, it MUST be invoked by the disk
    driver's dispatch routine, or by a disk driver's thread.  Likewise, all
    users, FSP threads, etc., must be prepared to enter a wait state when
    issuing the I/O control code to set the partition type for the device.

    Note also that this routine assumes that the partition number passed
    in by the disk driver actually exists since the driver itself supplies
    this parameter.

    Finally, note that this routine may NOT be invoked at APC_LEVEL.  It
    must be invoked at PASSIVE_LEVEL.  This is due to the fact that this
    routine uses a kernel event object to synchronize I/O completion on the
    device.  The event cannot be set to the signaled state without queueing
    the I/O system's special kernel APC routine for I/O completion and
    executing it.  (This rules is a bit esoteric since it only holds true
    if the device driver returns something other than STATUS_PENDING, which
    it will probably never do.)